public class CreateAccount extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_create_account);

    Button Submit_btn = (Button) findViewById(R.id.Submit_btn);

    final EditText Username_txt = (EditText)findViewById(R.id.Username_txt);
    final EditText Email_txt = (EditText)findViewById(R.id.Email_txt);
    final EditText Password_txt = (EditText)findViewById(R.id.Password_txt);
    final EditText VerifyPassword_txt = (EditText)findViewById(R.id.VerifyPassword_txt);

    final TextView Error_txt = (TextView)findViewById(R.id.Error_txt);

    final String Username_string = Username_txt.getText().toString();
    final String Email_string = Email_txt.getText().toString();
    final String Password_string = Password_txt.getText().toString();
    final String VerifyPassword_string = VerifyPassword_txt.getText().toString();


    Submit_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            if (!Password_string.equals(VerifyPassword_string)) {
                Error_txt.setText("Passwords must be matching");

            } else {
                Error_txt.setText("No Error");
            }
      }
}

Submit_btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {

final String Password_string = Password_txt.getText().toString();
final String VerifyPassword_string = VerifyPassword_txt.getText().toString();
    if (!Password_string.equals(VerifyPassword_string)) {
        Error_txt.setText("Passwords must be matching");

    } else {
        Error_txt.setText("No Error");
    }
}

Submit_btn.setOnClickListener(new View.OnClickListener()
 {
    @Override
    public void onClick(View view)
    {

    final String Password_string = Password_txt.getText().toString().trim();
    final String VerifyPassword_string = VerifyPassword_txt.getText().toString().trim();

        if (!Password_string.equals(VerifyPassword_string))
        {
            Error_txt.setText("Passwords must be matching");

        } else
        {
            Error_txt.setText("No Error");
        }
    }
 });

public void onClick(View view) {
    Password_string = Password_txt.getText().toString();
    VerifyPassword_string = VerifyPassword_txt.getText().toString();

    if (!Password_string.equals(VerifyPassword_string)) {
            Error_txt.setText("Passwords must be matching");
    } else {
            Error_txt.setText("No Error");
    }
}

String passwordString = "";

@Override
protected void onCreate(Bundle savedInstanceState) {

...
    final String Username_string = Username_txt.getText().toString();
    final String Email_string = Email_txt.getText().toString();
    final String Password_string = Password_txt.getText().toString();
    final String VerifyPassword_string =
                             VerifyPassword_txt.getText().toString();
   ...
}

public void onClick(View view) {

        if (!Password_txt.getText().toString().equals
              (VerifyPassword_txt.getText().toString())) {
            Error_txt.setText("Passwords must be matching");
        } else {
            Error_txt.setText("No Error");
        }

}

Submit_btn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {

    final String Password_string = Password_txt.getText().toString();
    final String VerifyPassword_string = VerifyPassword_txt.getText().toString();
        if (!Password_string.equals(VerifyPassword_string)) {
            Error_txt.setText("Passwords must be matching");

        } else {
            Error_txt.setText("No Error");
        }
  }

final String Username_string = Username_txt.getText().toString();
final String Email_string = Email_txt.getText().toString();
//final String Password_string = Password_txt.getText().toString();
//final String VerifyPassword_string = VerifyPassword_txt.getText().toString();


Submit_btn.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View view) {
         String passwordStr= Password_txt.getText().toString();
         String passwordConfirmStr=VerifyPassword_txt.getText().toString();
         if (!passwordStr.equals(passwordConfirmStr)) {
            Error_txt.setText("Passwords must be matching");
         } else {
            Error_txt.setText("No Error");
         }
      }
  });